Fix exception when display_expand_data=False for file-backed array. (#5235)

Co-authored-by: keewis <keewis@users.noreply.github.com>

Author: tomwhite

xarray/core/formatting.py

@@ -11,6 +11,7 @@
 from pandas.errors import OutOfBoundsDatetime
 
 from .duck_array_ops import array_equiv
+from .indexing import MemoryCachedArray
 from .options import OPTIONS, _get_boolean_with_default
 from .pycompat import dask_array_type, sparse_array_type
 from .utils import is_duck_array
@@ -507,10 +508,12 @@ def array_repr(arr):
     else:
         name_str = ""
 
-    if _get_boolean_with_default("display_expand_data", default=True):
+    if _get_boolean_with_default("display_expand_data", default=True) or isinstance(
+        arr.variable._data, MemoryCachedArray
+    ):
         data_repr = short_data_repr(arr)
     else:
-        data_repr = inline_variable_array_repr(arr, OPTIONS["display_width"])
+        data_repr = inline_variable_array_repr(arr.variable, OPTIONS["display_width"])
 
     summary = [
         "<xarray.{} {}({})>".format(type(arr).__name__, name_str, dim_summary(arr)),

xarray/tests/test_formatting.py

@@ -8,6 +8,8 @@
 import xarray as xr
 from xarray.core import formatting
 
+from . import requires_netCDF4
+
 
 class TestFormatting:
     def test_get_indexer_at_least_n_items(self):
@@ -472,6 +474,25 @@ def test_large_array_repr_length():
     assert len(result) < 50
 
 
+@requires_netCDF4
+def test_repr_file_collapsed(tmp_path):
+    arr = xr.DataArray(np.arange(300), dims="test")
+    arr.to_netcdf(tmp_path / "test.nc", engine="netcdf4")
+
+    with xr.open_dataarray(tmp_path / "test.nc") as arr, xr.set_options(
+        display_expand_data=False
+    ):
+        actual = formatting.array_repr(arr)
+        expected = dedent(
+            """\
+        <xarray.DataArray (test: 300)>
+        array([  0,   1,   2, ..., 297, 298, 299])
+        Dimensions without coordinates: test"""
+        )
+
+        assert actual == expected
+
+
 @pytest.mark.parametrize(
     "display_max_rows, n_vars, n_attr",
     [(50, 40, 30), (35, 40, 30), (11, 40, 30), (1, 40, 30)],